Floating piston structure



Nov. 9, 1937. v l'. F. BRoNsoN 2,098,612

FLOATING PISTON STRUCTURE Filed Feb. 27, 1956 liv/@Bronson Patented Nov. 9, 1937 UNITED STATES anni PATENT Eric 7 Claims.

This invention relates to engines and particularly to the pistons thereof and'to the kinematic chain of motion between the crank and the piston head.

The general object of this invention is to provide the body of the piston, which acts in the manner of a cross head, with a oating piston head associated with means whereby the piston body is guided in a straight line within the cylinder to thus eliminate wearing of one side of the cylinder and the confronting portion of the piston either upon the inward or outward movements of the piston.

Another object is to provide means which will dampen out the Vibrations commonly ascribed to the lateral component of the rod thrust against the housing wall or cylinder of a piston assembly.

A further object is to provide a detachable piston'head or floating head which is not connected to the body of the piston by bolts or like rigid connecting elements, but is connected thereto by a resilient element which yieldingly holds the head in place but permits rotary movement of the piston head around the longitudinal axis of the piston.

A still further object is to provide in a structure of this character a connecting means between the oating head and the body of the piston, which will permit the piston head to be readily put in place, which will positively hold the piston head in its position against detachment and against longitudinal movement with relation to the body of the piston when the direction of stroke changes but which will permit the disengagement of the iioating head from the body of the piston when desired.

A further object is to provide means whereby the interior of the cylinder and the exterior of the iioating head may be lubricated.

A still further object is to prevent any torsional stress, in a plane at right angles to the axis of the piston and cylinder, being applied to the wrist pin, and in this connection to provide means which willv hold the body of the piston against rotary movement around the axis of the piston and cylinder.

Still another obiect is to provide a structure of this kind in which the body of the piston acts as a cross head and is provided with guides extending toward the open end of the cylinder and operatively carried by the body of the piston,

these guides having outwardly projecting lugs and the cylinder having guide grooves within which said lugs reciprocate as the piston is reciprocated.

Other objects will appear in the course of the following description.

My invention is illustrated in the accompanying drawing wherein:

Figure 1 is a vertical sectional view of a cylinder, without the cyilnder head, and of the improved piston operating within the cylinder;

Figure 2 is a topplan view of the body of the piston without the oating head;

Figure 3 is a sectional view through the oating head of the piston;

Figure 4 is a vertical sectional view through the piston body showing the spring connection for the oating head partly broken away.

Referring now to Figure l, I@ designates a cylinder or housing having the skirt portion II. This skirt portion has upon its interior face the two longitudinally extending opposed grooves l2, the cylinder proper I0 shown as provided with the cooling space I3, which will be necessary if the improved piston and cylinder are used with an internal combustion engine. The cylinder head is not illustrated, as the form of this head depends entirely uponthe use to which the piston is put and would vary, depending upon whether this improvement is used on a steam engine, on an internal combustion engine or a heat engine.

Operating within the cylinder is a piston body I 4 which constitutes in effect a cross head. The body I4 is provided with the usual inwardly extending annular bearing bosses I5 having the usual babbitt linings I6. Each of these linings or bushings terminates short of the outer end of the corresponding boss I5. Disposed within the lining members is the bushing I'I which extends through the connecting rod and which has its outer ends extending almost to the exterior face of the body I4. Disposed within the bushing I'I is the wrist pin I8. To the middle of the wrist pin the connecting rod I9 is clamped in any usual or suitable manner, the head of the connecting rod being shown as being split, embracing the wrist pin and being clamped thereon by the bolt 20. This clamping head is disposed between the abutting ends of the bearing members in the usual manner. The lower end of the connecting rod is clamped upon the usual crank 2l.

The central portion of the body Ill is formed with an upwardly extending domical hollow boss 22 having a flat upper end face. 'Ihis boss is cast or otherwise formed in onepiece with the body I4 and is centrally apertured for the passage of a bolt 23. Mounted upon this flat central portion of the boss and held in place by the bolt 23, the nut of which bolt is disposed on the inside of the boss, is a resilient disk 24 of spring metal which has a flat central portion extending radially outward beyond the flat upper face of the central boss and having three prongs 25 extendlng downward and outward over the flat marginal portion of the upper face of the body I4.

Held in place upon the flat marginal portion 25 of the body I4 is a floating piston or piston head 2'! which has a circumferential wall 28, the lower end of this wall being formed with an inwardly extending annular flange 2S against which the edges of the prongs 25 bear. 'Ihis resilient metallic disk 24 with its prongs 25 yieldingly hold the head 28 against the flat margin 25 of the piston body or cross head I4. The exterior face of the wall of the floating head is formed with the usual packing ring grooves to receive the packing rings 3|). The lowermost or innermost packing groove has a pluralityV of apertures 3l extending into the hollow interior of the piston head for the purpose of lubricating the packing rings and Vthe exterior facerof the piston. The domical portion 22 of the body I6 is also provided with oil vents 32 which open into the space within the hollow interior of the piston head 2'I. The marginal portion 25 of the body I4 is also provided with oil vents 33 which open into the interior of the body I4. The bearare lubricated by means of coincident openings 34 in the bosses I5 and in the sleeves or bushings I6, these conducting oil to the interior bushings II. Thus as the piston is reciprocated oil will be splashed from the crank case up into the hollow body I4 through the ports 32 and 3| to the exterior face of the floating piston head and through the ports 34 to the bearing surfaces for the pin I8.

As before remarked, the lower end II of the cylinder is provided with longitudinally extending opposed grooves I2 and coacting with these grooves are the guide rods 35 which are carried loosely on the ends of the wrist pin I8,as shown most clearly in Figure 1, the upper end Vof each guide rod being formed with an eye`36 loosely embracing the extremity of the wrist pin and the upper portions of each guide rod being longitudinally slotted at 31, this slot extending into the eye. The lower end of each guide rod is formed with a radially projecting lug 38 which, as shown, is V-shaped in cross section and engages within the corresponding V-shaped groove I2. Each boss I5 and the bushing I Ii are both coincidently slotted at 39 to permit the passage therethrough of the upper end of the guide rod, this slot holding the guide rod from any oscillation with relation to the piston body I4. The wrist pin I8, of course, oscillates within the eyes 3B of these guide rods.

While I have referred to the member I4 as the piston body, it is to be understood that this body forms practically a cross head having bearings for the wrist pin but held from any rotation around the longitudinal axis of the cylinder by reason of what may be termed the crosshead guides 35 which extend to the guide grooves I2. If the element I4 is considered to be the cross head, then the part 21 may be considered to be the piston, but for the sake of clearness, I have referred to the portion I4 as the piston body and the member 2l as the piston head. As illustrated, the cross head or piston body I4 is formed withrapertures 40 to reduce the weight thereof and it will be noted that the guides 35 extend sufliciently far below they element I4 that in the reciproca-tions of the piston, the'upper ends of the grooves i2 are never uncovered or communicate with the space between the cylinder head and the piston head.

It will be noted that with my construction, the cylinder bore (that is, that portion of the cylinder within which the motive fluid actually operates) need be no longer than two-thirds the length of any present single block cylinder bores; also that by my construction the lateral thrust of the piston is dampened or resisted by the longitudinal guides 3.5 and the coacting grooves I2; that the piston is under no constraint whatever from the connecting rod; and that the wrist pin is supported against twisting strain. By the use or my complete assembly, I secure a dampening or cushioning of all shocks and jars which would tend to injure the cylinder, the piston, the piston guides, cross head, connecting rod or wrist pin. My l'ioating piston assembly operates with an easy, smooth motion under ig- The resilient disk 2li with its resilient prongs 25 is made of spring steel or alloyed metal plate and this disk acts in a sense as a baffle, baliiing the oil dash, balliing the unequal heat expansions and contractions and tending to preserve the even temperature necessary to tightly fitted moV- ing parts. This disk 24 also baffles or cushions the terrific vibration Acaused both within and from without, and, iiushed with oil, carries away or rather distributes the excess heat so generated and accumulated by the hot gases. It is, therefore, of distinct assistance to the practical fitting of the piston more closely than usual to the ignition chamber formed by the upper end of the cylinder. This disk, in other words, wards off the heat from the cross head much after the fashion of a baflie plate on a re door.

In the construction which I have described, the element I4 constitutes in effect a cross head or, in other words, a guide block for rotary reciprocation kinematic motion. The cylinder II constitutes a housing and the lower portion of this housing provides for the main guide elements causing a rectilinear movement of the guide block or cross head.

What is claimed isz- 1. A piston structure including a hollow body having an Youtwardly extending boss at its center, a resilient disk detachably connected to said boss and extending outward beyond the boss, and a piston head having an annular inwardly extending flange with which the resilient disk engages, the resilient disk urging the inner edge face of the head against said body.

2. A pistonY structure including a hollow body having wrist pin bearings, one end of the body being open and the other end closed, the closed end of the body being formed with an outwardly projecting central boss and with a flat rim surrounding and exterior to the boss, a hollow piston head having an inwardly projecting annular flange and a disk-like spring detachably engaged with the boss and having downwardly and outwardly extending marginal portions engaging the inner face of said flange and urging the piston head against the flat rim of the body.

3. A piston structure including a body having wrist pin bearings, the body being open at one end and closed at the other end, the closed end of the body having a centrally disposed outwardly projecting boss, the body exteriorly of the boss being formed with an annular flat rim, a diskshaped metallic spring resting against the outer end of the boss, a bolt holding said spring in place, a nut engaging the bolt and bearing against the inner face of the boss, a hollow piston head having piston ring grooves upon its circumferential face and formed at its inner end with a centrally extending annular flange, the spring having downwardly and outwardly inclined portions engaging against the interior face of said iiange and urging the edge face of the wall of the head against the flat rim of the body, the central boss of the body having apertures extending to the exterior face of the boss, the rim of the body having apertures extending into the exterior face of the rim and certain of the piston ring grooves having lubricating perforatio-ns extending to the interior of the head.

4. A piston structure including a body having wrist pin bearings thereon, a hollow piston head disposed outward of the body and having a centrally extending annular ilange at its inner end, and a resilient element detachably mounted upon the outer face of the body and having marginal portions extending radially outward and toward the body and engaging against the outer face of said flange and resiliently urging the head against the body,

5. A piston structure including a body formed to provide wrist pin bearings, a hollow piston head having a centrally extending annular flange at its inner end, and a resilient disk mounted upon the adjacent end of the body and having marginal radially extending portions separated from each other and bearing against the outer face of the flange on the head and resiliently holding the head against the body.

6. A piston structure including a body formed to provide wrist pin bearings, a hollow piston head associated with the body and having a centrally extending annular ange at its inner end, the body having an outwardly projecting portion at its center, a disk mounted upon said outwardly projecting portion and extending radially outward beyond the said portion and then radially outward and toward the body, the margin of the disk resiliently engaging the flange on the head.

7. A piston structure including a body formed to provide wrist pin bearings, a hollow piston head having a centrally extending annular flange at its lower end, a resilient disk engaged with the body at the middle of the disk and the body, the disk being constructed and arranged to be forced through the space dened by said annular ange on the head and then spring over said annular flange and engage against the outer face of the annular flange to resiliently engage the head with the body.

FRANKLIN F. BRONSON. 

